Psychometric Properties of Adding Four Bolt-ons to the EQ-5D-5L Compared to PROMIS-29 and Skindex-16 in Patients With Psoriasis or Atopic Dermatitis: A Longitudinal Study
Author(s)
Sandra Nael, M.Sc.1, Zhuxin Mao, Ph.D.2, Aureliano Paolo Paolo Finch, Ph.D.3, Maggie Abbassi, Ph.D.1, Samar Farid, Ph.D.1.
1Cairo University, Cairo, Egypt, 2Antwerpen University, Antwerpen, Belgium, 3EuroQol Research Foundation, Rotterdam, Netherlands.
1Cairo University, Cairo, Egypt, 2Antwerpen University, Antwerpen, Belgium, 3EuroQol Research Foundation, Rotterdam, Netherlands.
OBJECTIVES: To compare the psychometric properties of EQ-5D-5L—including an enhanced version with four bolt-ons (skin irritation, self-confidence, social relationships, and sleep)—against PROMIS-29 and Skindex-16, using longitudinal data from patients with mild to severe psoriasis (Ps, n= 125) and atopic dermatitis (AD; n=80).
METHODS: Participants completed paper-based questionnaires at baseline, 3-7 days later to assess test-retest reliability, and after 12-week to evaluate responsiveness. The psychometric properties of the EQ-5D-5L were assessed using both individual dimension levels and standardized Levels Sum Scores (LSSs). PROMIS-29 T-scores and Skindex-16 scaled summed scores (SS) were also calculated.
RESULTS: The addition of the four bolt-ons to the EQ-5D-5L effectively eliminated its overall ceiling effect, aligning its performance with that of Skindex-16. The bolt-on-enhanced EQ-5D-5L showed the highest explanatory power for EQ-VAS and Dermatology Life Quality Index (DLQI) in Ps (Adjusted R²=0.497 and 0.475). In AD, PROMIS-29 initially outperformed the standard EQ-5D-5L, but this advantage was neutralized after bolt-ons were added (Adjusted R²=0.419 for EQ-VAS and 0.381 for Scoring Atopic Dermatitis (SCORAD)). EQ-5D-5L LSS (with and without bolt-ons) and Skindex-16 SS significantly discriminated between different disease severities based on PASI and SCORAD (p< 0.01, one-way ANOVA). For test-retest reliability, Intraclass Correlation Coefficient (ICC) ranged from 0.78-0.88 (EQ-5D-5L); 0.83-0.96 (EQ-5D-5L+4 bolt-ons); 0.68-0.81 (PROMIS-29); and 0.81-0.88 (Skindex-16). Regarding responsiveness, Skindex-16 outperformed other tools (ES= -0.86 Ps, -0.78 AD), followed by the bolt-on-enhanced EQ-5D-5L (ES= -0.65, -0.69). Skindex-16 had the highest sensitivity to clinical changes in AD (rs =0.592), while EQ-5D-5L +4 bolt-ons was most responsive in psoriasis (rs=0.573).
CONCLUSIONS: The addition of bolt-ons to EQ-5D-5L significantly enhanced the psychometric performance of EQ-5D-5L, making it a strong alternative to Skindex-16 in Ps and AD, though with slightly lower responsiveness. PROMIS-29 demonstrated some strengths in AD but remained less sensitive overall.
METHODS: Participants completed paper-based questionnaires at baseline, 3-7 days later to assess test-retest reliability, and after 12-week to evaluate responsiveness. The psychometric properties of the EQ-5D-5L were assessed using both individual dimension levels and standardized Levels Sum Scores (LSSs). PROMIS-29 T-scores and Skindex-16 scaled summed scores (SS) were also calculated.
RESULTS: The addition of the four bolt-ons to the EQ-5D-5L effectively eliminated its overall ceiling effect, aligning its performance with that of Skindex-16. The bolt-on-enhanced EQ-5D-5L showed the highest explanatory power for EQ-VAS and Dermatology Life Quality Index (DLQI) in Ps (Adjusted R²=0.497 and 0.475). In AD, PROMIS-29 initially outperformed the standard EQ-5D-5L, but this advantage was neutralized after bolt-ons were added (Adjusted R²=0.419 for EQ-VAS and 0.381 for Scoring Atopic Dermatitis (SCORAD)). EQ-5D-5L LSS (with and without bolt-ons) and Skindex-16 SS significantly discriminated between different disease severities based on PASI and SCORAD (p< 0.01, one-way ANOVA). For test-retest reliability, Intraclass Correlation Coefficient (ICC) ranged from 0.78-0.88 (EQ-5D-5L); 0.83-0.96 (EQ-5D-5L+4 bolt-ons); 0.68-0.81 (PROMIS-29); and 0.81-0.88 (Skindex-16). Regarding responsiveness, Skindex-16 outperformed other tools (ES= -0.86 Ps, -0.78 AD), followed by the bolt-on-enhanced EQ-5D-5L (ES= -0.65, -0.69). Skindex-16 had the highest sensitivity to clinical changes in AD (rs =0.592), while EQ-5D-5L +4 bolt-ons was most responsive in psoriasis (rs=0.573).
CONCLUSIONS: The addition of bolt-ons to EQ-5D-5L significantly enhanced the psychometric performance of EQ-5D-5L, making it a strong alternative to Skindex-16 in Ps and AD, though with slightly lower responsiveness. PROMIS-29 demonstrated some strengths in AD but remained less sensitive overall.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
MSR175
Topic
Health Technology Assessment, Methodological & Statistical Research
Topic Subcategory
PRO & Related Methods, Survey Methods
Disease
No Additional Disease & Conditions/Specialized Treatment Areas